The Poly P10 has been discontinued,  Use both the PJ327 & the M22  as a replacement .  They must be used together. The M22 needs to have the compatibility setting set to 1.

Just plug the Plantronics P10 into your Operator Console, PBX or ACD, then plug in your Headset. The P10 delivers Plantronics' famous sound quality and ease of use. Its volume and automatic gain controls let you adjust incoming calls to a listening level that's comfortable for you. Comes with the handy Quick Disconnect feature and 10-foot coil cord.

Plantronics P10 Adapter Features:

• PJ 327 Plug-Prong Type Connection
• For use with Manufacturers Add-in or Built-in Jack
• Rotary Volume Control, Mute Switch
• Quick-Disconnect, for use with "H" Series Headsets
• Headset/Handset Switch, 10 Foot Coil Cord

 

Plantronics P10 Compatibility:

• Avaya Callmaster I, II, III, IV
• Avaya 302A/B/C Attendant Console
• Plantronics DuoPro - H151, H151N, H161N, H171. H171N, H181, H181N
• Plantronics DuoSet - H141, H141N
• Plantronics Encore - H91, H91N, H101, H101N
• Plantronics EncorePro - H291N, H301N, HW510, HW510V, HW520, HW530, HW540, HW710, HW720
• Plantronics Mirage - H41, H41N
• Plantronics SupraPlus - H251, H251N, H261, H261N
• Plantronics SupraPlus Wideband - HW251, HW251N, HW261, HW261N
• Plantronics Tristar - H81, H81N